https://github.com/python/cpython/commit/3d8fc8b9ae5beec852acf1a0e8102da030e... commit: 3d8fc8b9ae5beec852acf1a0e8102da030eeb1aa branch: main author: Sergey B Kirpichev <skirpichev@gmail.com> committer: vstinner <vstinner@python.org> date: 2025-01-24T11:05:52Z summary: gh-127937: Convert decimal to use PEP 757 import API (#127925) Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com> Co-authored-by: Victor Stinner <vstinner@python.org> files: A Misc/NEWS.d/next/C_API/2024-12-14-03-40-15.gh-issue-127925.FF7aov.rst M Modules/_decimal/_decimal.c diff --git a/Misc/NEWS.d/next/C_API/2024-12-14-03-40-15.gh-issue-127925.FF7aov.rst b/Misc/NEWS.d/next/C_API/2024-12-14-03-40-15.gh-issue-127925.FF7aov.rst new file mode 100644 index 00000000000000..6cf5fd2872cd43 --- /dev/null +++ b/Misc/NEWS.d/next/C_API/2024-12-14-03-40-15.gh-issue-127925.FF7aov.rst @@ -0,0 +1,3 @@ +Convert the :mod:`decimal` module to use :pep:`757` C API (export-import +integers), offering some speed-up if the integer part of the +:class:`~decimal.Decimal` instance is small. Patch by Sergey B Kirpichev. diff --git a/Modules/_decimal/_decimal.c b/Modules/_decimal/_decimal.c index 0def463c7d8b9e..b9abd8bd2e7a53 100644 --- a/Modules/_decimal/_decimal.c +++ b/Modules/_decimal/_decimal.c @@ -2336,15 +2336,16 @@ dec_from_long(decimal_state *state, PyTypeObject *type, PyObject *v, } if (export_long.digits) { const PyLongLayout *layout = PyLong_GetNativeLayout(); - uint32_t base = (uint32_t)1 << layout->bits_per_digit; - uint8_t sign = export_long.negative ? MPD_NEG : MPD_POS; - Py_ssize_t len = export_long.ndigits; - assert(layout->bits_per_digit <= 32); + assert(layout->bits_per_digit < 32); assert(layout->digits_order == -1); assert(layout->digit_endianness == (PY_LITTLE_ENDIAN ? -1 : 1)); assert(layout->digit_size == 2 || layout->digit_size == 4); + uint32_t base = (uint32_t)1 << layout->bits_per_digit; + uint8_t sign = export_long.negative ? MPD_NEG : MPD_POS; + Py_ssize_t len = export_long.ndigits; + if (layout->digit_size == 4) { mpd_qimport_u32(MPD(dec), export_long.digits, len, sign, base, ctx, status); @@ -3642,13 +3643,6 @@ dec_format(PyObject *dec, PyObject *args) static PyObject * dec_as_long(PyObject *dec, PyObject *context, int round) { - PyLongObject *pylong; - digit *ob_digit; - size_t n; - mpd_t *x; - mpd_context_t workctx; - uint32_t status = 0; - if (mpd_isspecial(MPD(dec))) { if (mpd_isnan(MPD(dec))) { PyErr_SetString(PyExc_ValueError, @@ -3661,12 +3655,16 @@ dec_as_long(PyObject *dec, PyObject *context, int round) return NULL; } - x = mpd_qnew(); + mpd_t *x = mpd_qnew(); + if (x == NULL) { PyErr_NoMemory(); return NULL; } - workctx = *CTX(context); + + mpd_context_t workctx = *CTX(context); + uint32_t status = 0; + workctx.round = round; mpd_qround_to_int(x, MPD(dec), &workctx, &status); if (dec_addstatus(context, status)) { @@ -3675,34 +3673,56 @@ dec_as_long(PyObject *dec, PyObject *context, int round) } status = 0; - ob_digit = NULL; -#if PYLONG_BITS_IN_DIGIT == 30 - n = mpd_qexport_u32(&ob_digit, 0, PyLong_BASE, x, &status); -#elif PYLONG_BITS_IN_DIGIT == 15 - n = mpd_qexport_u16(&ob_digit, 0, PyLong_BASE, x, &status); -#else - #error "PYLONG_BITS_IN_DIGIT should be 15 or 30" -#endif + int64_t val = mpd_qget_i64(x, &status); + + if (!status) { + mpd_del(x); + return PyLong_FromInt64(val); + } + assert(!mpd_iszero(x)); + + const PyLongLayout *layout = PyLong_GetNativeLayout(); + + assert(layout->bits_per_digit < 32); + assert(layout->digits_order == -1); + assert(layout->digit_endianness == (PY_LITTLE_ENDIAN ? -1 : 1)); + assert(layout->digit_size == 2 || layout->digit_size == 4); + + uint32_t base = (uint32_t)1 << layout->bits_per_digit; + /* We use a temporary buffer for digits for now, as for nonzero rdata + mpd_qexport_u32/u16() require either space "allocated by one of + libmpdec’s allocation functions" or "rlen MUST be correct" (to avoid + reallocation). This can be further optimized by using rlen from + mpd_sizeinbase(). See gh-127925. */ + void *tmp_digits = NULL; + size_t n; + + status = 0; + if (layout->digit_size == 4) { + n = mpd_qexport_u32((uint32_t **)&tmp_digits, 0, base, x, &status); + } + else { + n = mpd_qexport_u16((uint16_t **)&tmp_digits, 0, base, x, &status); + } if (n == SIZE_MAX) { PyErr_NoMemory(); mpd_del(x); + mpd_free(tmp_digits); return NULL; } - if (n == 1) { - sdigit val = mpd_arith_sign(x) * ob_digit[0]; - mpd_free(ob_digit); - mpd_del(x); - return PyLong_FromLong(val); - } + void *digits; + PyLongWriter *writer = PyLongWriter_Create(mpd_isnegative(x), n, &digits); - assert(n > 0); - assert(!mpd_iszero(x)); - pylong = _PyLong_FromDigits(mpd_isnegative(x), n, ob_digit); - mpd_free(ob_digit); mpd_del(x); - return (PyObject *) pylong; + if (writer == NULL) { + mpd_free(tmp_digits); + return NULL; + } + memcpy(digits, tmp_digits, layout->digit_size*n); + mpd_free(tmp_digits); + return PyLongWriter_Finish(writer); } /* Convert a Decimal to its exact integer ratio representation. */